Samsung AM072BXV Series Service Manual page 251

Piping Diagram
7-3 Functions (cont.)
7-3-2 Control (cont.)
7-3-2-4 Special operation modes (cont.)
Rotation defrost operation
▪ Purpose
Activate defrost mode on module-installed HR outdoor units in sequential order to improve heating efficiency.
▪ Concept
- Defrost operation is performed on outdoor units in sequential order when main heating mode is active on HR outdoor units.
- If rotational defrost mode is used 3 times consecutively, defrost operation will be performed on all the outdoor units when defrost
mode is turned on again.
▪ Control specifications in detail
- Enabled only when rotational defrost mode has been enabled by the Key option.
- Rotational defrost operation is performed in the following cases: two or more outdoor units are installed, the outdoor tempera-
ture is -5℃ or higher, rotational defrost has not been performed 3 times consecutively, the previous defrost mode was a general
defrost, or the duration of rotational defrost < the quantity of indoor units x 10 min.
- For the sequence of rotational defrost, the order of priority for outdoor units is followed.
- For the temperature and time conditions required to enter defrost mode, the same conditions as general defrost mode are applied.
- Condition(s) required to turn off defrost mode: Cond out temp ≥ 15℃ OR 12 min after defrost mode has started.
Actuator
Compressor
Outdoor EEV
Outdoor Fan
HR EEV
Main cooling valve
Cooling indoor
unit
Indoor
EEV
Heating
Indoor unit
Cooling indoor
unit
Indoor
Fan
Heating
Indoor unit
Time
Samsung Electronics
Outdoor units in defrost mode
Depends on the outdoor unit capacity
Active unit
Inactive unit
Active unit
Inactive unit
Active unit
Inactive unit
Active unit
Inactive unit
Maximum of 12 min
(86-110Hz)
Full close
0 step
Off
ON
General control
Required step for control of the superheat degree
General control
General control on inactive units
General control
Set fan speed
Mid fan speed
Off
Units not being in defrost mode
General control
General control
General control
General control
General control
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